ft<UU0 


I     S.  DEPARTMENT  OF  AGRICULTURE. 

division    OF    BNTOMOLOG  Y. 
BULLETIN    No.   20. 


&» 


y 


lit 


THE 


ROOT-KNOT  DISEASE 


OK    Till 


:h,  ORA-NGE,  anduTHER  plants 

IN 

FLORID 


DUE  TO  THE  WORK  OE  AXGUILLULA 


PRRl'ARKD,   UNDER    I  l[K    DIRK)   HON    OP    THF 


J.    C.     M.AL,     I'M.     1).,     M. 


W  A  S  H  I  N  I ;  T  ON: 

OOTIRNHKNT     PRINTING     DFFICK. 
l889. 


U.S.  DEPARTMENT  OF  AGRICULTURE. 

DIVISION    01      ENTOMOLOGY. 

Bulletin  No.  -in. 


THE 


ROOT-KNOT  DISEASE 


PE.  .  PL. 


IN 


FLORIDA, 


DUE  TO  THE  WoKK   OF  ANGUILLULA. 


r   i  in-:  i » 1 1 .  i  rri  >moi  ocist, 

l:V 

J.  C.  NEAL,   Pii.   I).,   M.   I). 


23495— Bull.  20 1 


WASH IN GTO X: 

GOVERNMBN1      PRINTING     "1   KICK. 
*9- 


Digitized  by  the  Internet  Archive 
in  2013 


http://archive.org/details/rootkOOusde 


LETTER  OK  TRANSMITTAL 


U.  8.  Department  of  Agriculture, 

Division  of  Entomology, 

Washington,  May  10,  188J). 
Sub  :  I  have  the  honor  to  transmit  for  publication  Bullctiu  No.  20  of 
this  Division,  beiug  a  report  of  studies  and  experiments  made  upon  the 
Anguillala,  which  is  the  cause  of  the  root-knot  disease  of  i  lie  Peach  and 
Orange  in  Florida,  l.y  .!.('.  Nral,  Ph.  1).,  M.  D.,  of  Lake  City,  Pla. 
Respectfully, 

C.  V.   UlLEY, 

Entomologist. 

lion.  J.  M.  KrsK. 

Secretary  of  Agricultun 


INTRODUCTORY  NOTE. 

I'm  several  J  ears  past  com  plain  I  has  In 'en  made  to  the  I  )i\  isiOD  of  En- 

tomologj  concerning  the  damage  done  by  various  species  of  Anguillu- 
inl.e.  which  affecl  the  roots  of  differenl  plant.-  in  differenl  sections  of 
the  country,  and  I  have  frequently  been  urged,  as  Entomologist,  to  in- 
vestigate the  matter.  I  have  always  lieeii  puzzled  to  know  what  repl\ 
to  make  in  such  cases,  as  no  American  iuvestigator  has  undertaken  a 
a  systematic  study  of  these  Nematodes,  ami  tbej  do  not,  in  a  zoological 
Reuse,  strictly  belong  to  the  Division  work.  I  have  contented  myself 
therefore  with  recording  the  various  tacts  of  injury  to  differenl  plants 
that  have  come  to  me  in  the  past  twenty  years,  and  sonic  microscopic 
notes  in  reference  to  the  specimens.  One  species  seems  to  do  consid 
erable  damage  to  certain  plants  in  greenhouses  in  the  North,  while 
another  is  equally  destructive  to  the  roots  of  trees  and  plants  in  the 
South,  particularly  in  Florida.  Towards  the  close  of  the  year  L887  the 
complaints  of  the  damage  done  by  the  Florida  root-inhabiting  species 
were  so  numerous  that,  at  the  request  Of  the  Commissioner  Of  A-ricul 
lure,  I  decided  to  conduct  some  investigations  as  a  pari  of  the  Division 
work.  The  demands  upon  the  resources  of  the  Division  arising  from 
its  more  legitimate  investigations  have  been  such  that  hut  little  time 
and  small  funds  could  be  spent  in  this  direction.  Dr.  J.  C.  Neal,  then 
of  Archer,  Fla.,  but  now  Entomologist  and  Botanist  of  the  Florida  A.g 
ricultural  Experiment  station  at  Lake  City,  a  diligent  observer,  and 
associated  with  me  in  previous  investigations  both  under  the  U.  s.  En- 
tomological ( 'om mission  and  under  this  Division,  was  commissioned  foi 
live  months  ami  instructed  to  make  as  careful  studies  and  experiments 
concerning  this  pest  as  it  would  be  possible  to  make  during  the  short 
time  of  his  employment.  His  work  was  done  between  February  l  and 
September  1, 18S8,  and  while  I  do  not  claim  for'Dr.  Neal,  any  more 
than  he  wotdd  himself  claim,  special  or  technical  knowledge  in  this 
branch  of  Zoology,  bis  work  is  not  without  scientific  interest.  The  in- 
vestigations have  been,  however,  from  a  practical  standpoint,  and  the 
results  more  than  justify  the  slight   expenditure.    The  Bulletin  makes 

no  pretense  to  he  a  scientific  treatise  on  the  life  history  of  these  worm-. 
but  is  in  the  main  an  effort  to  ascertain  a  suitable  remedy.  The  genera] 
literature  on  the  subject   has  not  been  at   Dr.  Neal's   command,  and  my 


time  is  so  fully  occupied  otherwise  that  I  can  do  little  or  nothing  at 
present  in  the  way  of  identification  of  species  or  of  comparing  Dr.  Neal's 
results  with  those  of  European  investigators,  which,  as  a  matter  of  fact, 
are  of  little  practical  importance.  The  study  of  the  full  life  history  of 
any  one  of  the  species  is  attended  with  much  difficulty,  and  will  re- 
quire much  time  in  field  and  laboratory;  while  the  technical  and  clas- 
sificatory  treatment  of  the  subject  should  be  undertaken  by  some  com- 
petent helminthologist. 

O.  V.  E. 


i 


LETTER  (>!•'  SUBMITTAL 


A  i;<  iir.K.  I'i.  \..  December  2,  1888 
Sir:  I  have  the  honor  to  anbmit  the  following  roporl  upon  the  root- 

knot  disease  ami  its  cause,  tin-  Anejiilliila. 

These  investigations,  conducted  under  yonr  direction,  began  in  Feb 
rnary,  1888,  ami  have  been  continncd  to  this  date. 

While  not  conclusive  in  all  respects,  they  are  at  leasl  contributions 
to  the  histor\  of  this  microscopic  post,  that  mav  eventually  lend  ti>  its 
subjection  or  to  the  mitigation  of  its  ravages. 

In  conclusion,  allow  me  to  express  i<>  yon  mj  thanks  for  your  aid  and 

guidance  during  the  preparation  of  the  report. 

Respectfully  submitted. 

.1.  C.  Neal,  M    I).. 

Sjll  ,  in  I    .1  Ijl  ,lt  . 

Prof.  C     X.   RlLKY, 

Entomolofju 

7 


THE  ROOT-KNOT: 

DEI  INITIOS 

An  abnormal  .mil  irregular  growth  of  the  subcortical  layer  ol  roots 
and  Bubterranoan  sterna,  characterized  bj  low  vitality,  the  resull  <>i 
an  invasion  of  the  tissues  l>.\  n  Nematode  worm.    (Note  1.) 

HI8TOR1  . 

Since 'the  earliest  settlement  < » t  the  South  Atlantic  and  (lull  state-. 

In  white  people  tins  diseased  condition  of  the  roots  of  trees  and  plants 
lias  been  recognized.      Note 

A  very  slight  inspection  has  shown  the  decaying  enlargements  of 
roots,  imt  the  cause  has  usually  been  attributed  to  a  lacfc  in  the  soil  of 
some  important  fertilizing  ingredient,  or  cureless  cultivation,  rather  than 
some  potent  exterior  influence. 

I  have  carefully  examined  all  sources  ol  informational  mj  command) 
and  can  find  mi  mention  of  the  root-knot  in  ;m,\  agricultural  paper  01 
hook  prior  to  the  year  1857. 

That  year  Hon.  1'.  .1.  Berckmans  established  a  nursery  at  Augusta, 
<ia..  and  soon  found  this  disease  prevalent  in  many  varieties  <>l  trees 
and  plants,  and  in  1881    Prof.  C.  V.  Riley  being  at  Augusta    was  shown 

the  effeel  of  the  disease  by  Mr.  Berckmans. 

In  I860  Mr.  Gilbert  Underdouk,  of  Nursery.  Tex..,  noted  the  disease 
in  his  flg,  grape,  ami  peach  stocks,  especially  in  damp,  undiaiued  loca- 
tions. 

In  1876  I  found  the  root-knot  prevalent  over  Florida,  and  learned  from 
old  residents  that  as  far  bach  as  L805  it  had  been  known,  and  from  time 
immemorial  had  been  dreaded  as  a  foe  to  gardens  and  groves. 

About  1874  this  disease,  however,  sprang  into  prominence,  owing  to 

the  influx  ofimmigrantS,  the  development  of  early-market  gardens  and 
the  sudden  rage  for  orchards  of  peaches,  figs,  and  oranges. 

Since  thai  time  the  agricultural  papers  have  contained  numeronsrci 
erences  to  this   disease.     My  own   attention  was  called    to  this  pest  by 
repeated  failures  to  grow  certain  plants  in   a    rich,  damp  spot    on   my 
farm. 

This  led  me  to  investigate;  and  sending  a  specimen  of  the  knotty 
roots  to  the  Agricultural  Department  at  Washington, elicited  theinfoi 
mation  th  it  a    microscopic  worm  was  the  cause  of  the  trouble,  but  that 
little  was  known  of  Mi  •  Nomatoid  family  to  winch  it  belonged. 


10 

Beyond  doubt,  the  disease  is  peculiar  to  the  South  Atlantic  and  Gulf 
coast  within  a  limit  of  150  miles  from  tide-water.     (Note  3.) 

Mr.  I'.  J.  Berckmans  remarks  on  this  score — and  I  know  no  better  au- 
thority— "  that  it  is  indigenous  to  a  large  portion  of  the  South  seems  un- 
deniable, as  I  have  seen  it  in  places  in  Georgia  and  Alabama  where 
neither  trees  nor  plants  had  ever  been  introduced  from  other  sections." 

Mr.  Onderdonk  also  states  a  similar  opinion.  Other  correspondents 
at  Mobile,  Ala  ,  and  in  Texas  confirm  these  statements. 


PLANTS  INVADED. 


-Uncultivated  : 
a.  Slightly  affected: 

Capselln    buraa-paatoria    (Shep- 

herd's  J'nrse). 
Rubus    villoana    <t    trivialia 
(Blackberry  and  Dewberry). 
Enpatorium  fooniculaceuni  (South- 
ern Dog  Fennel). 
Qnamoclit       vulgaris      (Cypress 
line). 


i>.  Badly  affected : 

Portalacit  oleracea  (Purslane). 
Sosuvium      pen  land  ruin      (Sand 

Purslane). 
Verbeaina  aiegesbeckia  et   ainu- 

ata. 
Artemisia  caudata  (Wormwood). 
Cbenopodrnm   botrya  (Jerusalem 

Oak). 
Amarantna     spinoana    (Careless 
Heed). 


The  above  list,  no  doubt,  will  in  time,  and  with  a  careful  investiga- 
tion, be  greatly  extended;  most  of  these  are  the  commonest  of  weeds  in 
old  iields  and  badly  cultivated  grounds,  and  the  Ghenopodium  alone 
would  be  an  ample  shelter  and  breeding- place  for  the  Anguillnla,  inde- 
pendent of  other  wild  or  cultivated  plants. 

The  Enpatorium  and  Chenopodiuin  are  perennials,  spread  rapidly, 
and  have  great  vitality,  and  for  years  it  has  been  noted  that  where  these 
weeds  abound  the  root-knot  exists  in  the  greatest  degree. 

The  Sesuvium  and  Portulaca,  both  with  fleshy  roots,  are  very  com- 
mon, and  are  an  easy  prey  to  the  worms,  but  my  experience  indicates 
the  Amarantus  spinosus  as  the  most  dreaded  and  destructive  agent 
in  the  spread  of  the  root-knot,  its  roots  being  apparently  the  favorite 
of  the  Anguillnla. 

in  Georgia,  my  correspondents  deem  the  Verbesina  and  Artemisia 
the  weeds  most  diseased,  but  in  Texas,  Mississippi,  and  Alabama,  the 
list  is  about  the  same  as  I  have  given  for  Florida.     (Note  4.) 

It  will  be  seen  that  it  will  be  impossible  to  determine  certainly  Un- 
original food-plant  of  this  pest,  as  it  seems  to  attack  the  roots  of  so 
many;  and  the  inference  that  any  tender  growth  not  impregnated  with 
a  decided  toxic  principle  may  be  invaded  is  a  doubtful  conclusion  to 
my  mind. 


II 


II.    <„/',., 

Useful, 
a    Sliffbtl)  offei  let! 

->  i  •  I  ■■(■■  hoi  bacon  in  el  barbo 
dense  I '  'otton ). 
Solannm   tuberosum  el  oscnlon 

1 1 1 in  t  l'ni,ii,<  nnd  Egg  I'lmi  j 
Capsionm  annunm    ' 
Bplnaoin  olei  v  on  I  Spinai  J  >. 
i      opba  raanihol    I 
Zen  mais  ( ( '01 »  | 
/..  Bftdlj  affected. 

The    Qenns    Brassii  i 
•  dbbagt ,  Kale,*  '■ 

R  Ipll.llllli  nil  l\  II-  i  RoWi 

Hibiaons  eaonlenl  na 
Plsum  sal  i  \  inn  |  /  • 
Araohia  hj  pogroa  |  Pea  »»'  I. 
I toliohos  cat iang    ' '■>»"  I'' a 
Pbaseolna  rnlgaria  |  Bean). 
Phaseolna     Innatua     el     nanna 

i  Beau). 
All    of    tin-    Qenns     Cucurbits 

(8qHO*h<  -.  •  '■ 
All  ..f  the  Gonna  Citmllns  -  Mel 

mi  ). 
All  ct"  the  Genna  Cucumie 

eumbi  r). 
Lyoopersicum    escnlontum    |  /•■ 

mnti)  l. 

Beta  vulgaris,  varieties  i  /■'■ 
d.  Ornamental. 
.1.  Blightlj  affecte* 

Bibisens  syriaons  et  coccinncna, 

.Mrsi'iiiliivaMllii'iiiiiiii.vai  ion 
oies  i  /'•<  -plant). 

Mik.un.i  seandons  I  Parlor  Try). 

Pharbitis    pnrpnrca    e(    al.    Bp. 
i  Morning  Glory I. 

Nolana,  ap. 

Potnnia,  ap.  »  Petun 

Bonsainganltia  basselloidea. 


II,     ( 'nil ii  nil  I    <  'on  I  limed. 
/.    I :  • .  1 1  n  .hi.  .  i.  .1. 

Konign  Mini itiin.i. 

[beris  unibi  I  I  i 

I.  i^i  ii. ii  1. 1  \  ulgai  i-  i  Qourd  |. 

Begonia,  ip.    /■'•  /■■ 

I  lahlin  \  ai  iabilia 

Flollanthna  an n una  i  Sunfloici  i  | 

( lolena,  \  1 1     p 

A i  li>  rani  he  i,  i  a   ip 

A  1 1 1 : 1 1 . 1 1 1 1 1 1  ■  \  :ir.  ip. 

Shrnbt  and  1 1  •  ■ 
I  Bofnl, 
a.  Slightly  affooted. 

( 'iii m  \  nlgai  i-  I  Bill*  >  nvet '  Oi  - 

ang 
Citrus  aurantinm,  \.u    Bp     0 

.  1 1  mon,  etc.). 
Viim.  \  ar.  Bp    {Oi  apt  I 
Pi  anna  mj  robolanua  I  1'hnn  |, 
Bronsaonettia  papyri fora  {Paper 

Mnlhi  i  , 

Morns,  \  or.  sp.  I  Vulberrg). 
Jnglana  cinoren  i  'I  aTnnt). 
Caryaolii  Dfonnis  (Pecan) 
h.  Badly  affected. 

Prnnns  domestics  I  Plu 
Prnnns  arineniaca     if  icot). 
Prnnns  vulgaris  I  /'<"■ 
Prnnns  commnnis  I  Union  1 1 
Fiona  caries  I  Fig). 
Jnglana  i  tglish  ll'nlniiti. 

Sal i x .  var.  sp.  (  Willows). 

d.  Ornamental. 

Spires  Borbi  folia, var.  Bp.    Spirea). 

Prnnns  nana  el  lam lata  I  Flow- 

i  ring    llmond  I. 
Bnddloia,  var.  ap. 
Gardenia    florida    I  Capt     ■> 
mine). 


This  lone:  list  embraces  tlio  greater  part  of  our  most  valnable  food- 
plants,  frnit-trees,  and  many  of  the  choicest  Bowers,  and  it  folly  justi- 
fies the  inquiry  now  made  as  to  the  history  and  means  to  prevent  the 

spread  of  the  disease  induced  !>y  the  Aniruillula. 

I  think  it  useless  to  endeavor  to  account  for  the  apparent  vagaries  oi 
the  A.ngnillnla,  as,  for  instance,  to  ascertain  why  the  mots  of  the  Prnnns 
vulgaris  arc  so  badly  nffected,  while  Prnnns  cerasns  are  unhurt  ;  or  why 
the  Logmninosffi  are  susceptible  and  the  Cmbcllifene  are  not.  It  is 
reasonably  Biiro  that  rapidly  growing,  soft  tissued  roots  are  better  sub- 
jects for  invasion,  expansion,  and  decay  than  those  of  slow  growth  and 


12 

denser  structure,  and  the  self-evident  corollary  is  that  methods  and  fer- 
tilizers promoting  a  rapid  succulent  growth  should  l>e  avoided  in  all 
locations  infected  with  the  root-knot. 

EFFECTS   OF   THE   INVASION   OF  TIIE   ANGIILLI'LA. 

1  have  found  mature  worms,  males  and  non-pregnant  females,  in  root- 
lets hut  a  few  days  old,  and  under  circumstances  which  involved  the 
necessity  of  invasion  from  without  the  root.     See  Experiment  Xo.  22. 

These  Anguilluhe  were  small  enough  to  enter  the  "  stomata" of  epi- 
dermal tissues,  active  and  strong  enough  to  even  penetrate  cell-walls,  or 
to  separate  cells  in  loosely  connected  tissues.  Once  within,  they  could 
easily  pass  through  the  Cienchymatous  system  of  the  Parenchyma  to 
any  portion  of  the  root,  and  1  think  it  not  unreasonable  to  infer  that  in 
this  manner  they  obtain  entrance  in  young  rootlets. 

Their  presence  causes  a  rapid  proliferation  of  cells,  resulting  in  a  soft, 
unnatural,  irregular  growth  of  the  root,  with  low  vitality,  and  a  varied 
effect  upon  the  plant  or  tree. 

The  Chenopodium,  Eupatorium,  Artemisia,  Amarantus.  Gossypium, 
Solanum,  and  Petunia  have  the  enlargements  usually  on  the  sides  of 
the  main  stem,  near  the  surface.  The  "  tap-root,"  descending  deeply  is 
rarely  affected,  and  the  plants  seem  slightly  affected  till  the  sub-corti- 
cal layer  is  fdled  with  worms  in  all  stages  of  growth.  This  checks 
growth,  either  by  their  absorption  of  the  nutrition  gathered  by  the  root- 
lets, or  obstruction  of  the  Cienchymatous  ducts,  the  food  supply  is  cut 
off  before  decay  is  visible,  the  leaves  wither,  the  steins  shrivel,  the  plant 
dies.    (Plate VIII,  la, 4 6.) 

The  roots  of  the  Okra,  Radish,  Turnip,  Cabbage,  Cucumber,  Melon, 
Cow-pea,  Peanut,  Tomato,  and  Egg  Plant  enlarge  enormously,  soon  be- 
coming little  else  than  masses  of  decaying  tissues.  The  plant  stops 
growth,  the  fruit  either  becomes  distorted  or  drops  prematurely,  the 
leaves  change  color  and  fall  off,  and  the  plants  die  so  rapidly  as  to  justify 
the  usual  expression  '•  struck  by  lightning,"  applied  to  the  fields  of 
Melons,  Cucumbers,  Tomatoes,  and  Cow-peas  so  often  badly  affected 
by  the  root-knot.     (Plates  I,  II,  III,  IV,  and  VIII.) 

In  nurseries  of  young  fruit-trees  the  greatest  mischief  occurs.  The 
soil  is  usually  carefully  prepared  by  heavy  fertilizing  and  culture,  and 
the  seeds  of  the  Peach,  Orange,  and  English  Walnut  are  sown  for 
stocks.  When  the  tender  shoots  first  appear  many  wither  and  die  at 
once,  others  grow  vigorously  till  the  end  of  the  first  season,  when  they 
are  usually  budded  with  known  and  valuable  varieties  of  fruit.  The 
next  spring  these  buds  put  out  tardily  and  make  a  weak  growth,  the 
leaves  become  spotted  or  yellow,  then  drop,  the  bud  dies,  feeble  strag- 
gling shoots  sprout  around  the  stem,  which  maintain  a  sickly  vitality 
till  the  first  drought,  when  the  tree  dies,  and  an  examination  dis- 
closes the  cause  in  the  knotty,  decaying  roots,  without  rootlets  or 
tibiilhe. 


13 

With  older  trees  taken  from  healths  Locatiousuud  sel  iu  iufoctuil  soil 
the  program  varies.  Tin-  Poach  aud  Fig  ofteu  grov  vigorously  oue  01 
two  years,  aud  bear  Eruil  thai  is  verj  proue  to  drop  immaturely,  tbou 
tin-  tree  takes  "ii  an  irregular  gro«  tb  of  stunted  limbs  aud  small  lea>  es. 
The  tips  of  these  limba  die  back  gradually  to  the  bodj  of  the  tree.  If 
the  soil  is  clayey  the  tree  will  put  oul  feeble  sprouts  ofteu  foi  several 
years. 

With  tlic  Pecan,  English  Walnut,  and  Willow,  older  trees  remain  sta 
tionui  >  a  year  or  bo  aud  die  \\  it  Ii  the  occasion  of  a  severe  drought. 

In  iii;iu\  cases,  especially  In  old  fields,  the  seeds  of  trees  and  plants 
I  >.  i  rely  germinate,  or  cuttings  hardlj  form  rootlets  till  thej  are  invaded 
and  destroy  f<\. 

In  all  of  these  cases  the  effect  is  to  deprive  the  stems  and  leaves  of 
fowl  and  moisture  j  the  knots  grow,  the  branches  do  not. 

The  annual  destruction  of  nursery  stock  is  enormous,  especially  the 
Peach,  Fig,  Willow,  Spiraea,  Buddleia,  Colons,  etc. 

In  the  sketches  taken  from  nature,  attached  to  this  report,  are  show  u 
typical  specimens  as  far  as  possible. 

The  Grape,  Fig,  Mulberrj ,  and  Orange  are  prone  to  circular  kuob  like 
knots  on  the  sides  of  the  larger  roots,  and  an  occasional  enlargement 
it  the  junction  of  small  roots.    (Plates  IV  and  VII. 

The  Peaoh,  Plum,  Walnut,  and  Spiraea  grow  irregulai  masses,  involv- 
ing the  whole  root  seemingly,    (Plate  \ 

Che  N\  illou ,  <  >kra,  etc,  enlarge,  and  the  decaj  is  usually  \  isible  tirsl 
at  the  extreme  tip  of  growth  from  the  central  stem.  (Plates  VI,  I,  aud 
II.) 

TERRITORY   OCCUPIED    BY    THIS    DISEASE. 

Barly  in  the  beginning  of  my  studies  of  the  Anguillula,  I  addressed 
letters  of  inquiry  to  most  of  the  leading  nurserymen  and  horticulturists 
in  the  United  States,  especially  those  in  the  southern  section,  asking  an 
examination  <>t"  diseased  trees,  and  inclosing  samples  of  the  rool  knot 
for  comparison. 

The  replies  I  received  are  conclusive  that  the  disease  is  unknown  be- 
yond any  point  in  the  interior  150  miles  from  the  coast. 

It  does  not  exist  except  in  locations  lice  from  extreme  cold,  and  (lie 
northern  boundary  is  not  far  from  the  January  isotherm  of  .In  .  as  shown 
in  the  No.  J.  Isothermal  Lines  of  the  I'.  S.  Signal  Service,  1881. 

Letters  from  the  Teaeh  districts  of  Michigan,  Maryland,  ami  New 
Jersey  complain  of  the  "  Yellows,"  but  investigators  do  not  report  tind- 
ing  the  diseased  roots  indicative  of  the  Anguillula. 

It  is  not  found  at  Denison,  Tex.  (Munson),  onlj  along  the  coast  in 
that  State,  and  then  only  in  sandy,  wet  locations.    (Onderdonk.) 

The  usual  dry  air  of  New  Mexico,  California,  and  regions  west  ot  the 
Mississippi  River,  with  the  summer  parched  soil  ot'  these  sections,  forms 
apparently  a  barrier  to  the  growth  aud  spread  of  the  disease,  but  coming 


14 

eastward  it  is  progressively  worse,  till  it  reaches  a  climax  in  Florida, 
which  seems  to  possess  the  requisite  soil,  humidity, aud  warmth  for  the 
proper  environment  of  tttii  Anguillula,  and  consequently  its  complete 
development  for  mischief  in  gardens  and  groves. 

Add  to  this  the  cultivation  of  special  food  plants  extremely  suscept- 
ible to  invasion  by  the  worm,  and  there  can  be  no  wonder  at  its  prodig- 
ious increase. 

TEMPERATURE. 

The  question  of  temperature  is  no  doubt  one  of  great  importance  in 
determining  the  boundaries  of  this  disease,  perhaps  more  so  than  food- 
plants  or  soils. 

The  soil  that  is  annually  frozen  from  0  to  10  inches  is  nearly  disin- 
fected from  the  worms,  especially  those  existing  in  a  free  state  in  the 
soil,  or  inhabiting  the  soft  l'oots  of  annual  plants,  and  this  may  explain 
why  southern  Michigan,  northeastern  Ohio,  and  New  Jersey,  with  as 
sandy  a  soil  as  Florida  or  south  Georgia,  still  escape  the  plague  in  the 
Peach  orchards. 

The  Ghenopodium,  Artemisia,  etc.,  abound  in  these  States,  aud  no 
doubt  are  the  habitat  of  Anguillula?,  but  the  continued  cold  reduces 
their  number  to  the  minimum  each  year,  and  the  hbrous-rooted  trees 
are  unharmed. 

Again,  in  some  cold  localities  the  trees  kept  in  hot-houses  arc  af- 
fected; those  without  in  open  ground  escape. 

Places  favored  with  hot,  dry  summers  and  cold,  wet  winters  will  not 
likely  ever  suffer  from  the  ravages  of  the  root  knot. 

My  experiments  are  conclusive  that  below  50°  in  fluid,  and  above 
that,  dry,  the  worms  are  inactive,  paralyzed  by  cold,  and  shriveled  by 
dryness  and  heat,  aud  the  inference  is  plain  that  parties  wishing  best 
results  must  either  choose  unsusceptible  stocks,  for  grafting  or  budding 
trees  liable  to  infection  by  the  Anguillula,  remove  to  favored  loca- 
tions, or  find  some  means  of  destroying  the  worms. 

The  arid  regions  of  the  "West  fill  one  indication,  the  others  are  still 
subjudiee,  but  in  a  fair  way  for  determination. 

SOILS. 

It  can  not  be  questioned  but  that  a  light,  sandy  soil  oilers  least  re- 
sistance to  the  progress  of  the  Anguillula  alter  its  liberation  from  de- 
caying roots  either  encysted  or  free. 

Experiments  with  air-dry  soil  show  that  water  penetrates  sand  in  half 
the  time  that  it  will  penetrate  clay,  and  over  huge  areas  of  cultivated 
land  the  proportion  would  still  be  greater  in  favor  of  the  sand. 

Loose  soils,  mixed  with  decaying  vegetation  and  humus,  offer  still 
better  facilities  for  irrigation,  and  this  explains  the  fact  that  locations 
highly  fertilized  with  composts,  stable  manure,  or  leaf-mold  show  the 
root-knot  (pucker  in  plants  than  compact  or  virgin  soils,  and  the  worst 


15 

results  ure  (band  in  gardens  planted  in  long  cultivated,  fully  fertilized, 
:  l  1 1  *  1  thoroughly  pulverized  areas. 

Moisture  is  an  essential  to  the  vigorous  growth  of  the  Auguillula, 
though  it  withstands  an  enormous  amouut  of  drying. 

The  cysts  shrivel,  pregnaul  females  become  irregulai  in  outline,  ins 

line   worms  si  ill  en  ami  remain  imle  I'm  itch   \\  illi  8U8peuded  vitality,  but 

resume  action  with  the  application  of  suffloieul  moisture.    (Note  5.) 
A  friable  soil,  with  compact  day  near  the  Burface  insuring  needed 

dampness,  presents  then  the  typical  envirpnmenl  foi  the  Auguillula, 

and  this,  alas,  also  is  regarded  in  this  section  as  the  must  advantageous 

location  for  a  garden  or  _;n>\  c. 
Another  vorj  favorable  locatiou  for  these  worms  is  the  boggj  bank 

of  a  lake  or  river,  where  there  is  r  mass  of  wet,  decaying  vegetation. 

EXPBRIMEN  is. 

A  series  of  experiments,  under  the  direction  of  the  Bntomologisl  of 
the  United  States  Agricultural  Department,  was  begun  in  February, 
1888,  to  determine  the  migration  and  life  history  of  the  Auguillula,  as 
well  as  to  investigate  the  effect  of  various  insecticides.  Thai  these  are 
not  complete  ami  conclusive,  is  owing  to  the  extreme  difficult}  of  trac- 
ing any  individual  worm  by  reason  of  its  size  and  its  surroundings. 

A  quantity  of  both  ordinary  Bandy  soil  and  clay  was  heated  several 
hours  to  a  temperature  of  tn'>    F. 

A  number  of  6  inch  earthen  pots  were  also  subjected  to  the  same 

heat.  The  earth  and  the  pots  were  tested  for  living  AuguilluliE  and 
found  sterile. 

Font  sterile  pole  with     '    cubic  fool  of  sterile  >.mI  in  oacb  pot. 
(•_'    B  Mo.  l,  nsing  aterile  clay  instead  ofsnrface  Boil. 

La  No  I,  nsing  yellow  anbsoil  from  infected  locations. 
\^  No.  :i,  using  day  snbsoil  from  infected  locations. 
-  No.  1.  nsing  infected  sui face  soil  from  infected  locations 

In  each  pot  were  planted  tour  seeds  of  the  ( Jow-pea  |  I  lolicbos),  selected 
because  of  its  ease  iii  germinating  and  great  susceptibility  to  the  An- 
guillnla. 

All  came  up  within  the  week  and  grew  fairly  well  ;   at  the  end  of  each 

week  one  plant  was  removed  and  the  roots  examined. 

In  Nos.  1  and  1'  UO  knots  were  visible  at  an\  Btage  of  growth  ami  the 

last  plant  grew  to  maturity. 

Iii  Nos.  3  and  1  the  plants  were  but  slightly  affected,  and  at  the  end 
of  the  fourth  week  each  remaining  plant  had  made  a  fair  growth,  de- 
spite the  terminal  roots  weie  becomiug  enlarged. 

In  No.  6  half  the  plants  died  before  the  appearance  of  the  third  leaf. 

and  the  remainder  made  a  sickly,  feeble  growth.    The  roots  were  badly 
knotted,  deca\  in  every  case  appearing  at  the  terminal  ends  of  the  root 
lets,  which  turned  brown  and  dropped  oil' at  the  slightest  touch. 

I  repeated  this  series  of  experiments,  using  small  seedling  peach  trees 
in  place  of  the  cow-peas.    The  results  were  similar — the  trees  in  Nos.  l 


1G 

ami  i'  growiug  vigorously,  with  fully  developed  roots  and  leaves;  in 

No.  ■>,  at  I  lie  cud  of  tour  mouths  the  trees  were   living,  but  feebly,  and 
tin-  roots  showed  signs  of  decay. 

In  No.  1  the  trees  had  grown  somewhat   better  and  had  a  brighter 

color,  but  the  roots  were  knotty. 

No.  5  showed  poorly,  leaves  smaller,  roots  quite  knotty,  and  one  tree 
dead. 

The  same  results  followed  using  the  Weeping  Willow  as  the  test 
plant. 

The  inferences  are :  That  the  Anguillula  is  destroyed  by  a  heat  of 
212°;  that  healthy  trees  set  in  infected  soil  soon  are  invaded  by  the 
Tree  Anguillula  in  the  soil  ;  that  soil  taken  from  the  depth  of  2  or  more 
feet  below  the  surface  is  comparatively  free  from  the  worms,  and  that 
clay  subsoil  is  less  infected  than  the  sand. 

Another  series  of  experiments  testing  the  effect  of  various  chemicals, 
fertilizers,  and  insecticides  was  tried,  using  four  sterilized  pots  in  each 
test,  the  pots  each  containing  n',,  cubic  foot  of  infected  sandy  soil,  and 
the  chemical,  at  the  rate  of  ,  „'„,,  of  the  weight  of  the  soil  d'  t  grains),  thor- 
oughly mixed  or  dissolved.  In  each  pot  was  planted  a  seedling  peach 
and  four  cow-poas. 

No.  G.  Tobacco  dust. 

7.  Tobacco  duel  with  24  grains  sulphate  potash 

8.  Tobacco  dust  with  •>!  grains  sulphide  potash. 
'.).  Tobacco  dust  with  "24  grains  sulphite  potash. 

to.  Tobacco  dust  with  24  grains  muriate  potash. 

11.  Tobacco  dust  with  24  grains  hyposulphite  soda. 

12.  Tobacco  dust  with  ','1  grains  sulphate  iron. 
115.  Tobacco  dust  with  24  grains  caustic  lime. 

I I.  Tobacco  dust  with 24 grains  uuleachcd  ashes. 

15.  Tobacco  dust  with  24  grains  sulphur. 

16.  Bisulphide  carbon. 

17.  Sulphate  potash. 

18.  Muriate  potash. 

III.  Unleached  ashes. 
20.  Caustic  lime. 

These  experiments  were  also  repeated  in  the  nursery  and  open  field 
on  small  peach  trees,  using  (102  grains  to  each  tree,  equivalent  to  lu\)0 
part  by  weight  of  the  soil.     (Note  6.) 

In  the  pots  the  results  in  Nos.  <i,  7,  10,  13,  and  li  were  very  encour- 
aging; the  peas  grew  to  maturity,  with  good  color  and  very  few  en- 
larged roots.  Nos.  8,  9,  11,  and  15  made  a  very  poor  growth,  and  died 
soon  after  the  third  leaf.  No.  12  died  immediately  after  sprouting,  as 
did  No.  16.  Nos.  17,  IS,  and  1!>  grew  nearly  as  well  as  Nos.  G  and  7  ; 
No.  20  made  a  tine  growth,  with  very  few  enlarged  roots.  The  peach 
trees  died  soon  in  Nos.  8,  9,11,  12.  15,  and  Hi.  made  a  lair  growth  in  Nos. 
(>,  7,  10,  13,  and  1  1.  were  killed  at  once  in  No.  lti,  and  grew  the  best  in 
Nos.  17,  IS,  19,  and  20.  " 

In  the  tield  Nos.  11,  KJ.  and' 8  appeared  to  at  once  kill  the  trees.  Nos. 


:i  ami  i)  ii  i.i  n>>  effect  visible,  Nos.  0,  7,  10,  uud  11  made  a  bcttui 
growth  ili.iu  N.i>.  17    50,     Itoot-kuol    was  preseul  on  all  bal    Nos.    13, 

I  I,  .in.l  20. 

Oil    Mill    In  <;rl    II..-.   .l|.|illr.l   ;'l    I  he  I  .lie   of  27    pounds  |o  I  he   I  Iit.    \i,  .. 

0,  l.;,  l  i,  17,  18,  19,  iiihI    U  gave  good  results,  especially  U  and  1 7,  <;  .1  n.  1 

is,  (i  ami  19.     riieae  mixtures  seemed  to  promote  n  vig s  growth  of 

health  \  roots,  ami  Nos.  u  ami  20,  rich  27  pounds  i'»  the  tree,  well  mixed 
witb  the  Burface  soil,  appears  to  !»•  as  neat  a  preventive  ol  the  ■•  kuol " 
a-  a'i>  thiug  I  ha\  e  11  ied. 

I  tried  the  bisulphide  of  carbon  without  any  effect  other  than  the  deatb 
of  the  trees,  some  fifty  or  more,  and  the  kerosene  emulsiou  to  saturation 
of  the  surface  soil  produced  a  similar  result,  uud  in  view  of  the  expense 

II  nd  labor  iu vol ved  [  did  not  repeat  the  experiment      (Note  7.) 

A  number  of  the  prepared  artificial  fertilizers  were  tried  :  those  con- 
taining ammonia,  guano,  bono,  aud  fish  produced  a  rapid  growth,  soft 
ami  easily  attacked  by  the  Auguillulfe. 

Ina  Qeld  near  raj  place,  beavilj  fertilized  with  a  bone  and  potasli 
compound,  the  roots  of  the  pea  nut  became  masses  of  kuotty  roots,  the 
worst  cases  of  the  disease  1  evei  saw,  and  peach-trees  growiug  iu  that 
Held  an-  ruined. 

1  have  found  nothing  of  value  when  applied  to  old  bearing  frail  trees, 
if  badly  affected,  as  any  insecticide  capable  of  absorption  i>\  the  roots 
invariably  has  killed  the  trees  when  used  to  the  amount  of  ,,',,,  the 
weight  of  the  surface  soil,  l  foot  in  depth  and  the  area  of  the  circle 
tilled  by  the  roots.  Alkaline  mi  Mures,  l'ii  to  10  pounds  to  each  tree,  or 
r  tustic  lime,  kainite,  muriate  and  sulphate  potash  or  wood  ashes,  naed 
several  years  in  succession,  have  come  nearest  a  enre,  destroying  no 
doubt  many  fret-  worms,  and  inducing  a  vigorous,  tough  growth  of  roots. 
more  difficult  of  penetration,  and  possibly  rendering  the  sap  ill  some 
way  obnoxious.     (Note  8 

The  addition  of  tobacco  dust  iu  large  quantities  supplies  nitrogen, 
and  makes  a  very  vigorous  growth  of  roots  aud  limbs.  Lt  also  seems  to 
have  considerable  preventive  effect  on  the  worms.  Experiments  con- 
ducted by  one  of  our  market  gardeners  has  convinced  him  that  the 
mixture  of  tobacco  dust  and  muriate  of  potash  in  old  Holds  iu  great 
measure  prevents  the  ravages  of  the  Anguillula  in  <  >kra,  Cabbage,  ami 
ISgg  plant,  ami  he  has  adopted  this  as  a  .standard  fertilizer  for  all  his 
products.  I  have  seen  his  use  of  this,  and  am  neaih  prepared  to  sus- 
tain his  views.  Kainite  is  no  doubt  fully  as  good,  but  further  export 
menting  is  necessary. 

Another  series  of  experiments  was  made  upon  plants  to  determine 
the  time  and  degree  of  infection. 

No.  21.  Sterilized  pots  with  , ,; .,  cubic  foot  of  atei  ile  soil,  iu  which  four 
cow- peas  were  planted    at    various   depths,  one  half  inch,  three  fourths 
inch,  and  1  inch,  were  covered  1  inch  with  infected  earth  and  kepi  wa- 
tered.    The  results  showed  infection  of  the  roots  in  about  the  same  ra- 
23495— Bull.  20 2 


18 

tioas  the  (list  a  nee  from  the  surface.  Reversing  the  process,  putting  the 
infected  soil  below,  showed  the  roots  affected  soonest  in  the  peas  planted 
deepest,  indicating  but  little  action  in  the  worms  outside  of  that  pro- 
duced by  the  percolation  of  water, 

No.  22.  Another  series  of  pots  were  watered  with  muddy  water  from 
infected  earth,  and  though  the  pots  contained  sterilized  sod  the  loots 
of  the  peas  were  badly  affected.  Microscopic  investigation  of  the  per- 
colate showed  both  free  and  encysted  Anguilluhe.     (Note  9.) 

No.  23.  Tots  with  sterile  soil  had  one  transplanted  infected  peach 
seedling  in  each,  and  four  cow-peas. 

The  trees  soon  died,  and  very  shortly  afterward  the  peas  showed  the 
infection,  those  nearest  the  dead  peach  roots  the  most  markedly. 

In  a  spot  of  new  and  non-infected  ground  several  trees,  Peach  and  Pig, 
were  planted.  The  central  tree  was  knotty-rooted  and  died  in  a  few 
months:  the  next  year  the  loots  of  the  nearest  trees.  \r>  feet  away,  became 
knotty  nearest  the  dead  tree,  and  now,  after  the  lapse  of  tour  years, 
the  disease  extends  to  the  tips  of  the  roots  of  all  the  Fig  and  Peach  trees 
in  a  circle  120  feet  distant  each  way  from  the  original  infected  tree. 

In  another  case,  in  a  nursery  on  high  pine  land,  clay  subsoil  and  free 
from  disease,  a  number  of  peach  roots,  badly  knotted,  were  brought 
from  a  distance  and  heeled  in  for  a  week.  The  disease  spread  in  all  di 
rections  from  this  nucleus. 

Again,  in  another  peach  nursery  was  a  spot  of  low,  damp,  black  soil. 
There  was  no  root-knot  the  first  year  it  was  planted  in  peaches;  the 
seedlings  grew  well.  The  second  year,  a  few  trees  Mere  found  in  this 
spot  with  enlarged  roots  and  destroyed.  The  third  year,  hardly  a  tree 
escaped,  the  disease  extending  along  the  thickly  set  rows  of  seedlings 
upward  and  in  all  directions  on  to  the  higher  land  from  the  hollow  spot 
first  infected. 

In  another  case,  clean  fibrous-rooted  trees  were  heeled  in  a  day  or  so 
and  planted  in  non-infected  ground.  The  next  year  proved  the  most  of 
them  diseased. 

These  cases  prove  conclusively  that  in  areas  not  infected  the  disease 
can  be  easily  introduced  (1)  by  planting  infected  trees;  (2)  by  the  use 
of  composts  of  muck  and  weeds  from  infected  soils;  (3)  by  the  distribu- 
tive action  of  water  and  air,  the  water  carrying  particles  of  soil  and 
worms  downward  from  an  infected  elevation,  or  by  dry  soil,  frag- 
ments of  dry  roots,  desiccated  free  or  encysted  worms  carried  in  the  air 
during  sand  storms,  whirlwinds,  or  the  heavy  currents  of  air  preceding 
storms  that  often  blow  "  bare  "  acres  of  plowed  land  and  overwhelm  ad- 
jacent fields  with  the  soil  thus  borne  on  the  wind;  (4)  soil  containing 
these  worms  I  have  no  doubt  has  been  carried  on  the  feet  of  men  and 
animals  and  deposited  in  healthy  fields,  forming  the  nucleus  of  a  de- 
structive agency,  months  afterward  made  visible  by  its  effects. 

Instances  are  not  wanting  that  can  not  be  explained  except  by  some 
such  theory  of  contagion  and  manner  of  travel. 


I'J 

REMEDIES. 

1.    l)i;  \iN.\i;r.. 

>  1 ; 1 1 1  \  gardens  .ind  orchards  are  badlj  located  ou  mmIn  partly  satu- 
rated w  it  1 1  water,  oithoi  at  tho  inorgius  of  rn  urs  oi  lakes  oi  on  rieb  de 
posits  of  vegetable  remains  botb  \om  aud  damp. 

Tbe  reasous  for  this  cboice  are  general!)  tbo  superior  quality  of  tbe 
land  and  tbe  rapidity  of  growth  induced  by  the  moisture,  bid  iu  the 
territory  infected  i>\  the  Anguillula  the  beat  aud  rich  soil  cause  precisely 
the  looseness  of  tissue  so  favorable  to  the  Bpread  of  the  worms. 

A.  dry  soil,  with  solid  root-growth,  is  on  tbe  contrary  unfavorable; 
hence  iu  many  Ideations  drainage  lias  eutirelj  changed  the  character  of 
the  land,  so  that  peaches  and  figs  grow  ulnae  thoj  would  not  before. 

Experiments  in  Texas  con Qrin  this  fnllj  and  suggest  the  utility  of 
thorough  drainage  of  wet  locations,  or,  better  yet,  the  avoidauce  of  such 
places  for  groves  and  gardeus. 

In  this  connection  it  may  be  remarked  as  one  of  the  not  expected 
results  of  the  ••  New  Agriculture"  in  maintaining  a  permanently  damp 

sod  by  means  of  water  pipes  below  the  Surface,  that  w  hen  it  is  ill  VOgUC 

we  will  have  not  only  a  great  increase  oi  crops  bul  a  greater  increase 
of  "root  knot"  iii  the  cabbages,  beets,  radishes,  etc.,  thus  grown.  What 
effect  the  ingestion  of  Anguillulae  will  have  upon  the  human  economy 

remains  to  be  seen  ;  as,  so  far  as  I  know,  no  record  occurs  of  experiments 

having  been  tried  to  ascertain.    (Note  l<».) 

2.  Peost. 

In  many  places  north  of  29  there  is  cold  enough  each  year  to  at 
times  freeze  the  surface  a  considerable  depth.  Where  this  occurs,  b\ 
plowing  the  soil  at  the  beginning  of  winter  and  at  times  during  thai 

season,  it  IS  reasonable  to  suppose  ureal  destruction  of  the  free  Auguil- 
lula1  will  ensue. 

3.  FlKK. 

The  value  of  heat  in  the  destruction  of  the  germs  of  the  root  knot 
lias  been  often  demonstrated  in  Florida,  nsnalK  unwittingly,  and  the 
lesson  taught  has  been  in  a  measure  lost 

In  clearing  old  fields,  badly  infected  with  the  worms,  as  shown  by  the 

crops  of  cotton  or  peas,  it  is  customary  to  burn  log  heaps  and  stumps  ; 
if,  then,  peaches  and  figs  have  been  planted  on  this  burned  land  tbe 
result  has  been  freedom  from  root  knot  for  a  series  of  years. 

Such  trees  make  a  vigorous  growth  and  bear  well,  while  adjacent 
trees,  not  on  burned  ground,  wither  and  die. 

It  would  seem  practicable  in  this  wooded  section  to  easily  build  small 
compact  heaps  of  chips,  wood,  pine  knots,  even  dry  weeds  and  grass, 
pver  the  area  of  say  2  feel    radius  from  each   tree  stake  prior  to  pi: 


20 

ing,  burn  the  heap  to  ashes,  excavate  the  soil  as  far  as  heated,  and  re. 
new  the  fire  (ill  (lie  .subsoil  is  readied  and  the  depth  of  al  least  a  fool 
of  soil  in  all  is  thoroughly  sterilized  by  heal. 

In  many  eases,  where  wood  is  plenty,  dead  standing  timber  to  be 
removed,  and  stumps  to  he  burned,  the  plan  would  succeed  to  stake 
out  the  held  and  build  a  log-heap  at  each  stake;  but  if  not  convenient, 
the  annual  growth  of  weeds  and  grasses,  well  dried,  will  furnish  fuel 
enough. 

4.  Sterile  Soils.    (Note  11.) 

Among  the  early  settlers  of  Florida  the  practice  prevailed,  when 
planting  trees,  of  digging  out  the  soil  to  the  depth  of  1'  or  more  feet 
and  tilling  in  around  the  tree  with  clay  or  yellow  subsoil  obtained  from 
virgin  land  and  li  or  more  feet  below  the  surface.  This  plan  succeeded, 
in  that  it  surrounded  the  tree  with  sterile  soil  till  it  formed  firm  roots 
and  a  hardened  epidermis. 

My  investigations  show  that  in  infected  soils  the  deep  roots  are  but 
slightly  atl'ected  in  comparison  with  those  near  the  surface,  and  that 
the  greatest  destruction  prevails  in  young  trees,  nursery  stock,  and 
plaids  having  surface  roots. 

If  a  tree  acquires  age  aud  the  roots  reach  deep  subsoil,  the  Anguil- 
lulse  do  little  damage.  Hence  the  utility  of  using  clay  or  subsoil,  derived 
from  virgin  forest,  around  newly-set  trees. 

This  old  plan  deserves  attention  and  can  be  recommended;  Vail  since 
the  war,  in  their  haste  to  promote  the  growth  of  groves  and  gardens. 
the  later  horticulturists  reverse  this  method,  imbed  the  young  tree  in 
surface  soil,  and  use  nitrogenous  fertilizers  to  encourage  rapid  develop- 
ment, this  certainly  causes  increase  of  the  root-knot. 

5.  Disuse  of  Land. 

Keeping  land  clean,  free  from  all  growth  for  two  or  more  years,  has 
proved  of  great  benefit  if  done  before  trees  are  planted.  I  believe  the 
worms  require  living  tissues  to  develop  in,  and  deprived  of  this  they 
would  die,  probably  within  the  limit  I  have  given. 

In  many  places  where  the  soil  has  not  been  cultivated  for  a  long 
series  of  years,  and  the  Broom  Sedge  Grass  has  exterminated  all  other 
weeds,  I  have  failed  to  find  any  traces  of  the  Anguiilula,  and  I  regard 
this  as  confirmatory  proof  that  disuse  of  laud  prevents  the  root-knot. 

6.  Disuse  of  Easily  Infected  Crops. 

In  most  of  our  Southern  States,  where  the  (Movers  and  Buckwheat 
will  not  prosper,  it  has  been  the  almost  universal  custom  to  substitute 
the  Cow-pea  as  a  soil-renovator.  Drilled  or  broadcast  it  is  the  great 
crop  for  "laving  by"  corn,  and  as  a  second  or  third  crop  after  rice, 
oats,  or  market  garden.  Very  few  groves  or  orchards  but  have  annu- 
ally from  one  to  three  crops  of  pea-vines  plowed  in  for  fertilizing. 


21 

Again,  as  n  "  flrsl  crop,"  after  ulenring  ofl  the  timber,  il  is  in  general 

use  For  new   land.     Few   plants  ar»  litivc  to  the  attacks  of  the 

\  n  -ii  1 1  in  l.i. ; ii ill  few  have  roots  so  badlj  infected  with  these  worms,  and 

this  common  oastom  of  planting  the  Com  pea  is  mentioned  onlj  to  lie 

condemned,  as,  if  continued,  in  time  all  groves  and  gardens  in  these 

sainh  soils  will  be  failures. 

The  Lespedeza  stri;it;i  (Japan  Olover),  Desmodium  molle  (Bi 
Weed),  and  Riehardsonia  Bcabra  (Mexican  Clover),  will  prove  Que  sub- 
stitutes for  the  Cow  pen  as  forage  and  fertilizer  If  the  Tow  pea  mnsl 
he  grown,  keep  it  away  from  garden  and  orchard,  and  ;it  planting  time 
use  large  quantities  of  Bome  strong  alkaline  fertilizer  on  the  soil.  The 
economical  babil  of  plauting  market  gardens  in  orchards  should  be  dis 
couraged. 

It  is  c;is\  to  see  the  reason  and  the  danger  from  the  nso  of  ammo- 
niacal  fertilizers  so  necessary  to  induce  rapid  growth  of  vegetables,  and 
the  spread  of  the  Angnillulte  from  the  roots  of  tin'  .Melons,  <  Incumbers, 
etc.  to  the  trees.  Manv  instances  of  this  sort  can  be  seen  over  the 
South,  and  should  serve  as  warning  to  <>nr  horticulturists  in  the  future. 

I  believe  that  in  badly  infected  grounds  some  relief  could  bo  given 
by  drilling  tlic  Cow-pea,  and,  when  in  bloom,  cutting  <>iv  the  stems  for 
forage;  then  to  plow  ami  carefully  rake  np  the  roots  in  piles  for  burn- 
ing when  dry  enough.    This  method  of  destroying  the  infected  roots  of 

Okra,  Melons,  etc.,  and  the  roots  of  the  Chcuopodium,  etc.,  would  no 
ilonbl  bo  of  great  value  in  small  areas,  and  even  in  larger  fields,  by 
the  aid  of  improved  machinery  for  gathering  the  roots. 

It  needs  only  the  mention  that  plauting  ol  trees  from  infected  local- 
ities should  be  avoided  ;  even  those  not  liable  to  the  disease  themselves 
ina\  carry  soil  containing  A.ugnillui(B  among  the  roots. 

1  have  noted  that  Hie  Peach  and  Pig  obtained  from  Northern  nur- 
series Beem  extremely  easy  to  take  the  disease,  far  more  bo  than  the 
native  stocks.  1  only  moution  the  fact,  but  have  not  ascertained  the 
reason. 

7.  ixsr.ri   Enemies. 

I  have  found  but  one,  the  small  blackish  brown  ant  that  inhabits  rot 
ton  wood  and   decaying  roots — very  common  in  this  section — the  Sole- 
nopsis  xyloui. 

This,  when  the  roots  of  the  Okra,  Pea,  etc.  begin  to  decay,  burrows 
into  the  tissues  and  drags OUt  the  pregnant   AnguillulflD  for  destruction. 

I  was  puzzled  at  first  to  limit  he  dead  roots  of  the  Okra,  Melon.  Peach, 
and  Pig  free  from  cysts  or  pregnant  worms,  thongh  in  partially  rotting 
enlargements  I  found  plenty  of  Anguillula. 

Closer  and  extended  examination  showed  this  ant  in  the  act  of  de 
vouring  the  enlarged  worms,  and  its  service  to  the  orchardist  is  be- 
yond value  in  this  respect 

Inasmuch  as  a  dry  soil  is  favorable  to  ant  life,  it  will  be  readily  seen 
how  drainage  is  useful  in  aiding  the  propagation  of  this  tiny  destroyer. 


22 

Upon  crashing  a  mature,  pregnant  worm  various  forms  of  micrococci 
arc  visible  by  the  microscope  as  existing  within  the  Anguillula,  evi- 
dently not  hurtful,  and  when  seen  exterior  to  the  worm  seem  not  preju- 
dicial to  its  life;  but  more  study  is  needed  on  this  point. 

8.  Use  of  Vermicide  Fertilizers. 

Experiments  looking  to  the  adoption  of  some  mixtures  capable  of  de- 
stroying the  worms  while  in  the  root  tissues  have  not  proved  a  success. 
The  use  of  smaller  quantities  per  acre  than  one-tenth  of  1  percent,  of 
the  surface  soil  for  1  foot  in  depth  and  10  feet  radius  to  each  tree — 
about  a  ton  to  the  acre — produced  no  perceptible  effect  on  the  disease, 
and  a  greater  amount  injured  the  trees. 

The  use  of  bisulphide  carbon,  kerosene  emulsion,  and  various  arsen- 
ical solutions  destroyed  so  great  a  percentage  of  the  trees  that  on  that 
account,  and  the  expense  of  application,  it  was  abandoned. 

Alkaline  mixtures  have  done  better,  and  will  bear  repetition,  espe- 
cially the  sulphites  and  muriates. 

For  nursery  stock,  it  no  doubt  will  pay  to  thoroughly  incorporate 
some  of  these  chemicals  with  the  soil  some  weeks  before  planting  seeds, 
cions,  or  young  trees,  using  it  at  the  rate  of  at  least  one-tenth  of  1  per 
cent,  of  the  surface  soil  cultivated. 

Alkaline  fertilizers,  as  hard-wood  ashes,  muriate  and  sulphate  of  pot- 
ash, kainite,  or  ash  element  produce  a  hard  growth  but  little,  if  any, 
affected  by  the  root-knot.  Usually  the  fertilizer  is  applied  in  too  small 
a  quantity.  Not  less  than  3,000  pounds  to  the  acre  should  be  used  to 
produce  the  required  effect,  one-half  in  December,  the  remainder  in 
May. 

A  fertilizer  containing  a  small  percentage  of  carbolie  acid,  carbolates, 
tbymol-cresol,  or  an  easily  decomposed  sulphite  would  no  doubt  be  valu- 
able in  this  infected  section. 

9.  Non-infected  Stocks. 

After  all,  I  believe  the  use  of  trees  that  are  not  susceptible  to  the 
root-knot,  for  stocks  on  which  to  graft  or  bud  the  susceptible  varieties 
is  the  proper  solution  of  the  root-knot  problem.  The  matter  of  location, 
soil,  fertilizer,  and  prevention  then  need  not  worry  the  intending  or- 
chardist.  Find  the  disease- proof  tree  and  the  thing  is  done,  and  most 
of  my  experiments  have  been  directed  to  secure  in  some  measure  this 
result. 

It  is,  perhaps,  too  soon  to  say  that  complete  success  has  been  realized, 
but  the  gain  is  perceptible. 

For  the  Orange  I  can  recommend  the  hardy  bitter-sweet  or  sour 
species  as  nearly  disease-proof  and  a  vigorous  grower. 

The  Citrus  trifoliata  and  the  Japanese  "  Unshiu,"  or  Satsuma,  both 
seem  resistant,  but  the  time  of  trial  lias  been  too  short.  This  last  is  a 
slow  grower,  with  dense  roots,  and  promises  to  be  the  best  of  any  of  tin4 


Citrus  family.  Its  hardiness,  freedom  from  thorns,  and  vigoi  recom. 
mend  it. 

Grapes  of  the  Viuifera  type  as  well  as  those  of  the  Estivalis  group  arc 
Bnbject  to  the  root-knot,  if  growu  on  their  owu  roots,  1ml  grafted  into 
stocks  of  the  Oordifolia  or  Vulpina  races  have  made  superb  growths 
free  of  the  disease. 

I  have  ton im I  no  stock  for  Fig  "i  Mnlberrj  that  baa  stood  the  test. 

For  the  Peach  famibj  either  the  seedlings  ol  the  Wild  Goose  Plain, 
the  Man.imia.  or  the  recently  introduced  Japauese  Plums,  Kolsey,  Sal 
smiia,  or  Ogru,  arc  valuable.  Three  j  ears'  test  of  the  Marianna  prove 
that  for  that  time,  at  least,  the  roots  resisted  the  Anguillula  and  were 
free  from  knots.  When  the  peach  died  the  Myrobolan  was  infected 
slightly,  and  eveu  the  native  plums  suffered  with  the  disease.  It  is  too 
soon  to  give  an  unqualified  appiw  al  of  this  as  a  stock,  but  so  far  it  is 
thi>  very  best,  growing  from  cuttings  and  very  rapidly,  making  a  tree 
that  is  nearly  borer- proof  as  well  as  free  from  the  Anguillula?. 

Some  seedlings  of  our  American  lMuins  are  destined  to  replace  the 
Teach  as  a  stock,  nuless  the  Japanese  varieties  prove  superior. 

I  have  found  nothing  of  value  for  the  English  Walnut  a-  a  Mock,  nor 
for  the  Weeping  Willow. 

1  have  indicated  tin-  probable  Hue  of  act  ion  to  mitigate  or  prevent  the 

disease  in  gardens — the  use  of  alkaline  fertilizers,  the  exposure  to  frost, 
the  gathering  of  diseased  roots  to  hum,  the  removal  of  certain  weeds, 
and  the  disuse  of  land  and  cow   peas. 

KXI1M    OF    DESTRUCTIVE   BFFECTS  OP   THE   DISEASE. 

Within  the  district  infected  by  the  Anguillula  it  would  be  well  nigh 
an  impossibility  to  give  even  an  approximate  idea  of  the  losses  sus- 
tained each  year  by  the  farmer,  the  gardener,  and  the  horticulturist 

from  the  ravages  of  this  worm. 

All  over  the  southern  section  of  the  United  States  hundreds  of  market 
gardens  have  been  planted  at  an  immense  outlay  of  time  ami  money,  only 
to  have  the  fields  of  vegetables  blighted  from  this  mysterious  trouble,  as 
if  scorched  by  tire  or  frost.  Thousands  of  trees  have  been  planted  only 
to  dwindle  away  and  die;  and,  as  the  defect  has  been  usually  ascribed 
to  the  fertilizer  or  the  climate,  the  injury  has  been  enormous,  while  the 
real  cause  has  not  been  suspected,  and,  as  far  as  I  know,  no  effort  made 
to  ascertain  a  remedy.  The  Orange  is  slightly  affected  now,  lint  in  the 
future,  when  the  soil  will  he  filled  with  cysts  and  worms.  Grange  trees 
will  he  as  uncertain.  I  fear,  as  the  Peach  or  Pig  at  the  present  time. 

From  the  best  testimony  I  can  get,  in  the  early  days  of  the  white  im- 
migration, except  in  damp  locations,  peaches  grew  without  an\  disease  . 
save  the  ••  Borer."  Now,  in  many  places,  the  trees  that  do  well  are  the 
exception,  and  in  these  locations  it  is  idle  waste  of  time  labor,  trees,  and 
fertilizers  to  attempt  the  culture  of  an  orchard. 

In  such  infected  spots  the  usual  program  is  to  apply  some  costly 


24 

ammoniaeal  manure  to  the  land,  cultivate  early  vegetables  between  the 
trees;  then,  after  that  crop  is  removed,  sow  the  land  in  cow-peas.  The 
result  is  bewildering.    Next  year  the  unfortunate  planter  is  discouraged 

to  liml  many  of  the  trees  dying  back,  the  vegetable  crop  with  knotty 
roots  and  irregular  fruit. 

Another  heavy  fertilizing,  another  crop  of  peas,  and  that  spot  is  done 
for.  The  disgusted  farmer  tries  another  vocation,  and  gives  over  the 
place  to  weeds  and  desolation. 

With  young,  closely-sel  rows  of  trees  the  disease  causes  greatest  dam- 
age, spreading  rapidly  from  tree  to  tree. 

In  market  gardens,  especially  the  Tomato,  Cucumber,  Melon,  and 
Squash,  the  Anguillula  often  either  destroys  the  plants  before  fruiting 
or  reduces  the  size  of  the  fruit  till  it  fails  to  pay  expenses. 

A  number  of  disastrous  failures  with  gardens,  that  have  come  to  my 
notice,  no  doubt  resulted  from  this  cause. 

LIFE   HISTORY   OF   THE   ANGUILLULA. 

The  study  of  this  microscopic  worm  has  been  exceedingly  difficult, 
and  many  points  in  its  history  are  not  yet  fully  ascertained. 

The  limit  of  its  existence,  periods  of  growth,  sexual  characteristics, 
generation,  variation  of  form,  and  the  precise  action  occasioning  the 
abnormal  growth  in  roots,  are  all  undetermined  questions  which  will 
take  a  long  continued  series  of  observations  to  solve.     (Note  12.) 

As  first  observed,  a  mass  of  cells  appears  within  the  uterine  corn u a, 
cells  averaging  .,,, 7,,,,,  inch  in  diameter,  arranged  in  bands  from  T, 
to  roooo  'ncn  i"  width,  reaching  across  to  the  walls  of  the  uterus. 
(Plate  XX,  A,  B.)  These  bands  appear  at  the  smaller  end  of  the  uterus, 
beginning  from  1020°00  to  ,,,-,"0,1  inch  from  the  free  extremities,  extend 
jng  downward  ,  0:i,"„n  to  ,  ,;„"„„  inch.  Lower  down,  these  cells  show  a  ten- 
dency to  aggregate  into  irregular  masses  (Plate  XX,  15,  U),  then  into 
ovate  forms,  eventually  becoming  ovals  ,,,;;,,,,  by  ,,,",,',,,,  inch. 

At  first  these  cysts  have  no  epidermis,  but  a  thin  coating  appears 
and  thickens  as  they  approach  the  normal  size  of  l,1,,',,,,  inch  in  length 
and  ,„',;;,„  inch  in  width.     (Plate  XX,  D,  2.) 

During  the  life  of  the  female  the  cysts  form  rapidly,  until  the  whole 
uterus  becomes  enormously  enlarged,  and  contains  cysts  in  every  stage, 
from  the  primary  agglomeration  of  cells  to  free  Anguilluhe.  (Plates 
XIX  and  XVIII.) 

The  decay  of  the  environing  root  exposes  the  pregnant  female  to 
changes  in  weather,  and  with  a  slight  increase  in  heat  the  contraction 
of  the  exterior  expels  the  contents  of  the  uterus  and  disperses  them. 

This  in  most  cases  appears  to  be  through  the  upper  segment,  though 
often  it  occurs  through  the  fissure  in  the  head.     (Plate  XIX.) 

The  cyst  at  first  is  a  solid  mass  of  granular  cells.  (Plates  IX,  1,  and 
X.  1.)  It  divides  centrally  at  the  shorter  axis  (Plates  IX,  2,  3;  X,  2, 
20,4):  each  half  repeats  tin's  process  till  four  or  live  segments  are  visible- 

A  longitudinal  fissure  then  appears,  causing  eight  segments  (Plates 


25 

I  \ ,  <i,  7 ;  ;m n I  \ ,  i">.  10,  18)  j  the  \\  alls  "t  the  segments  are  absorbed 
each  side  the  central  long  fissure  l'l  rte  IX,  8,  10,  15,  10,  I ■'.  18),  w  bicli 
extends  to  the  margin  of  the  oysl  in  ouo  direction,  and  upon  separation 
ai  thai  end  motion  begins,  and  the  Anguillulu  awakes  to  life  and  ac 

t ton.    (Plates  IX,  17,  is;  nnd  XI,  I.) 

The  growth  within  the  cyst  continues  till  the  worm  attains  n  length 
of  ,,',,;:,,  inch  or  more,  nnd  a  central  diameter  of  ,  .  im-h  ;  the  cysl 
raptures,  the  worm  is  free  (Plate  XI,  2,  3,  7),  leaving  the  emptj  shell 
Bbrnnlcen  and  lorn.    (Plato  \  I.  I.  I". 

I'p  to  tli  is  |  it  ii  nt  I  have  failed  to  discriminate  the  sexes.     Both  appeal 
blunt  at  one  end,  which  is  marked  with  a  fissure  ,,,,',,,,,  inch  to 
inch  iii  length,  often  with  a  circular  binge-like  termination  (Plate  \  1 1, 
So,  la,  <!",  7<(,  and  XIII,  l".  2a,  3a)  extending  into  a  tortnous  channel 

;,,„  inch  in  diameter  and  averaging      '       inch  in  length;  then  the 

remainder  of  the  worm  becomes  a  mass  of  cells  of  various  sizes  to  within 

„  inch  or  inch  of  the  extremity  oi  tail. 

These  cells  nt  times  appear  with  a  sinuous  channel  dear  from  either 

end  (Plate  XII,  I),  or  with  Wreaks  in  t  heir  continuity  ( I  Male  XII, 2, 3),  or 

granular  masses  interspersed  (Plates  XII.  i;.  7,  and  XIV,l,2),or  as 

II  no  colls  irregnlarly  arranged.     Plate  XIII,  1,  2,  3.)    Occasionally  the 

whole  interior  appears  as  a  solid  mass  of  cells.      |  Plate  X  I  I.  6.) 

I    have  not  discovered  the    method   of   impregnation,  bnl    at  an  early 

period  tapid  changes  in  shape  begin  in  the  female.  (Plates  XVI,  2  to 
15;  XVII,1  to9;  XIV;  XV ;  and  XII,  5, 0,  7, 8.  The  enlargement  is 
preceded  by  the  formation  in  both  upper  and  lower  thirds  of  the  liodj 

of  dark  masses  of  cells  that  eventually  unite  (  Plates  X  I  V,  •  ">.  A.I'.;  1, 
.""»,  A,  P>,  0,  and  0;    XV,  2,  3),   then   by  the    time   the    worm  leaches  the 

age  represented  in  Plate  XVI,  11,  12;  PlateXVI, 3,4,  become  changed 
into  a  bicornate  ovarium  or  aterns,  which  at  lull  term  attains  the  length 

ol  ,  inch  in  many  coils,  and  contains  one   hundred  and   fifty  or  one 

hundred  and  sixty  full-sized  cysts. 

The  shapes  and  si/.-s  of  these  pregnant  females  vary  greatly, and  I 
believe  are  the  result  ol'  the  environment.  In  suit  tissues  of  the  Cow 
pea.  Radish,  and  the  like  rapidly -growing  plants  they  attain  a  transt  erse 
diameter  of  inch,  and  a  length  of  ;  ;,;;:;„  inch.    The  tail  is  reduced 

to  a  short  spine  (  Plates  \  I  V,  .;  ;  and  XV.  _'.  3),  which  disappears  later 
on,    as   the    worm    approaches  the    transverse  diameter  of  inch. 

(Plate    XVII,  3,    I. 

I'll.'    thickness  of  the    exterior   wall    varies   from    ,„,;,.„   inch   at    the 
lower  part   of  the  bodj   to  inch  at  the  vertex,  and  is  exceedingly 

tongh  and  resistant.  In  color  it  appears  yellowish  by  transmitted  light, 
but  a  brilliant  white  by  reflected  light  When  fully  developed,  il  is 
partly  transparent,  showing  the  coils  of  the  uterus  with  its  cysts.    The 

exterior  is  granular  or  corrugated,  especially  near  tl head"    Plates 

XIV, 0, and  XIX  .  and  with  an  apparently  radiate  arrangement  of  cells 

from  a  center  near  the  tail,  or  perhaps  marking  the  disappoaram f 

that  appendage.      Plate  X  X  I 


26 

The  head  varies  from  a  form  like  Plates  XVII,  3, 4, 7, 9,  and XVI,  9, 
L2, 13,  11,  to  dial  shown  by  Plates  XVI,  10, 11, 15;  XVII,  2, 5, 8,  and 
XVIII,  the  neck  from  a  mere  contraction  of  the  body,  Plates  XVII,  G, 
and  XVI,  15,  to  a  long  tube,  as  in  Plates  XVI,  L4,  and  XVII,  9. 

The  body  varies  from  almost  a  globe  (Plate  XVI.  9, 13j  to  an  oval 
(Plate  XVI,  1 1 ;  XVII,  9),  or  nearly  a  cylinder.     (Plate  XVI,  15.) 

The  worms  found  in  woody  tissue  are  usually  of  the  forms  of  Plates 

XVI,  10,  11,  ami  XVII,  5,  8;  in  soft  tissues  like  Plates  XVI,  14,  and 

XVII,  7,  9,  but  I  am  unable  to  understand  the  reason  of  this  variation. 
In  roots,  as  a  rule,  the  bodies  radiate  from  the  central  axis  of  the 

root  witli  the  "  heads"  to  the  axis. 

When  once  enlargement  of  the,  body  begins,  the  worm  becomes  a  fix- 
ture, and  remains  incapable  of  progression  in  any  direction;  the  en- 
largement is  gradual  and  the  cells  of  the  root  tissues  become  smaller 
by  the  pressure,  forming  a  rigid  wall  on  every  side  of  the  worm. 

How  long  the  worm  exists  is  an  unsolved  problem  which  I  hope  to 
solve  in  time. 

Apart  from  vegetable  tissues,  I  have  noted  signs  of  life  in  the  An- 
guillula  after  being  kept  air- dry  six  months,  but  have  no  record  of  any 
reliable  experiments  with  the  worms  in  the  roots  ;  but  the  vitality  is 
very  great. 

When  motion  is  first  perceived  in  the  cyst,  the  worm  is  an  average 
of  roouo  'nca  ™  length  and  10JUo  extreme  thickness;  soon  after  it  be- 
comes free  it  enlarges  and  lengthens  till  it  casts  its  skin,  which  it  does 
as  shown  in  Plate  XI,  5,  leaving  the  old  skin  shrunken  as  at  (!,  same 
plate;  a  fragmentary  cast  is  seen  on  Plate  XII,  1,  but  1  have  not  de- 
termined the  number  of  times  in  its  life  it  sheds  the,  skin,  as  it  is  rare 
to  find  a  perfect  cast  for  measurement. 

Among  the-  thousands  of  Anguilluhe  I  have  examined,  therearea  great 
many  variations  and  arrangements  of  cells  that  are  not  easily  explainable. 
Plates  XV,  XIII,  and  XII,  5,  8,  7,  fi,  exemplify  some  of  the,  most  marked, 
riate  XIII,  2,  3,  is  very  singular;  a  cyst-like  form,  with  segments. 
Also  at  3,  a  peculiar  arrangement  of  cells,  large  and  small ;  in  fact.  I 
have  never  found  two  worms  exactly  similar  in  the  grouping  of  cells; 
the  resemblance  is  general,  but  with  wide  variation  of  details.  The  ex- 
amples given  in  the  plates  justify  this  conclusion,  sketched  as  they  were 
from  living  specimens. 

The  arrangement  of  the  cysts  in  the  uterus  is  generally  as  shown  by 
Plates  XVIII,  XIX,  and  XX,  though  that  often  becomes  changed,  as 
indicated  in  Plate  XXI.     (Note  13.) 

In  mature  and  apparently  aged  worms.  I  have  found  as  many  as  a 
dozen  free  worms  within  the  uterus,  having  attained  motion  and  liber- 
ation there. 

In  plates  showing  the  changes  in  vegetable  tissues,  "A''  refers  to  the 
enlargements  and  nests  of  Anguilluhe.  "  B"  to  spots  of  decay. 


27 


NOTES 

v>"1 1'  i      Owing  to  a  look  .>i  literature  on  the  subject,]  hav<  pro  vis allj  named 

this  worm   iii'iiiilliihi  arenaria,  but  il  maj  belong  to  li  an  Angnil 

lnla.il  isverj  in  n  Hio  A.  ItroviapinoBua,  bnl  as  (ho  spine  disappears  In  mature  forma, 
I  havo  called  tin-  \    irenai  in. 

Won   '.'      rbis  information  rnmo  from  one  of  tin  il  of  il 

from  ilw  Spanish  reeldente  in  I-  " 

Won  I  Letters  received  from  corrcapondenta  at  nenrlj  over]  important  town  gave 
ill.'  data 

Woni  i      Mi  mra    Berokmana,  Ondordonk,  Munaon,  and  Stello  arc  rel I  to. 

Won  G     [kept fall j  dovoloped  pregnant  fomaloa  in  a  watch  glass  drj  foi  six  months, 
and  when  wot,  thoj  expanded,  and  the   grown  worms  within  the  cyata  in  the  ut< 
roan  mod  mot  ion. 

Won  6.    The  average  weight  ofaenbie  foot  ofordinarj  sandy  surface  soil  ia(5,( 
grains,  equal   to  B6  08   ponnda  avoirdnpoia;   tin-  at  the  ti  mperatnre  ol  70  .  tho  -..il 
being  air-drj . 

Ni>i  !  7.— 'I'lif  qnantity  required  to  saturate  1 1  uhic  fool  «  aa  2.3  gallons  of  tho  kero 
Bono  emnlaion. 

Wont  8.  The  amount  of  lime  need  «a^  .'<•  ponnda  to  tho  tree,  fort j  nine  trees  to  tin 
acre. 

Notk  9.— Water  ponred  upon  tho  pots  percolated  through  tho  soil  and  out  at  tin 
bole  in  the  bottom  '>f  the  i »•  -t .  Thia  was  allowed  to  evaporate  considerably  and  exam- 
ined with  magnifier  350  diameters,  eye-piece  It.  objective  one-half  inch. 

Wotk  10. — Radiahea  and  turnips  are  very  BU8coptiblo  to  thoAnguillnla.  (See  Plate 
III.  draw  ii  from  actual  Bpeoimen,  natural  Bize. ) 

Wont  11.  A  common  practice  among  tho  '  old  time  Blavea,  who  toll  mo  it  waa  tho 
mlo  made  bj  the  old  whites  aa  fat  back  as  1805.  The  reason  they  gavewas"tho 
peach  lovea  olay  and  yellow  Band." 

Won  12.  I  .  ..ii  i,i  only  approximate  the  growth  and  development  l>y  tho  use  of  audi 
plants  as  the  Cow-pea  and  Radish— planting  Boed  in  infected  soil,  and  at  certain  dates 
pulling  up  tho  plants  and  examining  the  knots,  making  n  carefnl  sketch,  drawn  t.. 
seal...  each  limo.     All  attempts  at  cultivating  in  flnids  failed. 

Wotb  13.  i:>  softening  the  oxterior  with  a  Bolntion  of  caustic  potash,  snipping  oil 
the  head  and  gontlj  pressing  the  body  in  fluid,  « ith  a  cover  glass,  tin  nterus  exuded 
a--  Bhown  in  Plate  XIX 

o 


EXPLANATIONS  TO  PLATES. 


PLATE  I. 

i  of  Con   Pea,  showing  enlargements  oansed  by  Angnillnla:  A,  enlargement 
and  nests;  B,  spots  of  decay.     (Origins 

PLATE  II. 

Roots  of  Okra,  show  Lng  enlargemi  nts  oansed  by  Angnillnla  :  A,  enlargements  and 
:  B  spots  of  decay.    (Original.) 

ri.\  l  l.  ill 

Roots  of  Radish,  showing  enlargements  oansed  by  Angnillnla:  A.  enlargements  and 
nests;  B,  spots  of  decay.    (Original.) 

PLATE  IV. 

Roots  "i  Grape  [  Black  Hamburg  ],  showing  enlargements  oansed  by  Angnillu 
enlargements  and  nests;  B,  spots  of  decay.    (Origin  i 

PLATE  V. 

Roots  of  Peach,  showing  enlargements  oansed  by  Angnillnla.     (Original.  | 

PLATE  VI. 

-  of  Weeping  Willow,  showing  enlargements  oansed  by  Angnillnla — natural 

(Origin  i 

PLATE  VII. 

Roots  <>f  Fig/showing  enlargements  oansed  by  Angnillnla — natm  l  'nor- 

mal.) 

PLATE  VIII. 

kion  of  root  of  Okrr»,  showing  enlargements  oansed  by  Angnillnla  :  '.'.  I 
same;  '■'.  Grape, sam< — enlarged  four  times:   i,  Weeping  Willow,  same— natural  - 
A,  enlargements  and  nests;  B,  spots  of  decay.     (Original.) 

PLATE  IX. 

Reproductive  cysts  which  form  in  the  nterns  of  the  female  Angnillnla:  1.  fast 
lid  mass  of  granular  cells ;  2, 3, segmentation  or  division  into  two  parts;  4. 
86,  .">,  5a,  6,  segmentation  into  four  parts:  7,  longitudinal  tissnn'  appearing, which 
causes  segmentation  into  eight  parts;  8,9,  1".  11. 12,  L3,  1 1. 15, 16,  IT,  1-,  walls  of 
mentB absorbing  each  side  of  the  central  longitudinal  fissure  which  extends  to  the 
margin  of  the  oyst  in  one  direction,  until  upon  separation  at  that  end  motion  hegins — 
greatly  enlarged.     (Original.) 

- 


30 

PLATE  X. 

Reproductive  cysts  (continued) :  1,  la,  first  stage  ;  2,  3,  4,  26,  bi-seginentation  or  di- 
vision into  two  parts;  5,  6, 7, 8, 9, segmentation  into  four  parts;  10,11,12,13,14,15, 
16, 17, 18,  segmentation  into  eight  parts— greatly  enlarged.     (Original.) 

PLATE   XL 

Developed  or  free  Anguilluhe  within  the  reproductive  cysts:  1,  free  Auguillula 
within  cyst  not  yet  broken  ;  2, 3, 7,  cyst  broken  ;  4,4a,  empty  shell  of  cyst  from  which 
Auguillula;  have  emerged  ;  5,  young  worm  casting  skin  ;  6,  empty  skin  cast  by  young 
worm— greatly  enlarged.     (Original.) 

PLATE  XII. 

Growth  of  Anguillula* :  1,  cast  skin  of  young  worm  ;  2,  3,  4,  5,  6, 7,  8,  worms  showing 
bluntness  at  one  end,  with  fissure  haviug  a  circular,  hinge  like  termination  at  A,  and 
granular  masses  of  cells  within — greatly  enlarged.     (Original.) 

PLATE  XIII. 

Growth  of  Auguillnlae  (continued):  1,2,  3,  worms  showing  masses  of  fine  cells  irregu- 
larly arranged  within,  and  fissure  at  blunt  end  with  circular,  hinge-like  termination 
at  A — greatly  enlarged.     (Original.) 

PLATE  XIV. 

Growth  of  Anguillul®  and  chauges  within  the  female  :  1,  2,  female  worms  showing 
granular  masses  within;  3,  4, 5,6,  chauges  in  shape  in  the  female,  preceded  by  for- 
mation in  upper  and  lower  thirds  of  body  of  dark  masses  of  cells,  A,  B,  C,  which 
eventually  unite — greatly  enlarged.     (Original.) 

PLATE  XV. 

Changes  within  female  Anguillula?  (continued) :  1,  2,  3,  enlargements  in  shape  of 
the  female,  with  formation  of  masses  of  cells  at  A — greatly  enlarged.     (Original.) 

PLATE  XVI. 

Changes  in  form  of  female  Anguilluhe:  1-15,  outlines  showing  chauges  in  form, 
from  leaving  the  reproductive  cyst  until  the  female  is  herself  filled  with  cysts,  also 
showing  changes  in  the  form  of  the  head  aud  disappearance  of  the  tail — greatly  en- 
larged.    (Original.) 

PLATE    XVII. 

Changes  in  form  of  female  Anguilluhe  (continued) :  1-9,  outliues  of  changes  in  form 
of  body  and  head,  with  the  disappearance  of  the  tail — greatly  enlarged.     (Original.) 

PLATE  XVIII. 

Gravid  female  Auguillula,  showing  contracted  head  and  neck  as  in  some  females, 
and  the  arrangement  of  cysts  in  the  uterus — greatly  enlarged.     (Original.) 

PLATE  XIX. 

Arraugement  of  cysts  in  uterus  of  female  Auguillula  aud  expulsion  of  young  worms 
through  fissure  in  the  head — greatly  enlarged.     (Original.) 


;{1 

PLATE  W 

An. in^iii t  of  oyata  Id  nterns  oJ  female  Angnillnla  i  continued      A  B,  oyata  nr- 

raii^<-<l  in  i>;unls  reaching  aerom  to  the  walla  of  the  uterna ;  B  gAtion  of  oella 

Into  irregular  maaeee  within  the  nteraa;  C  D,  aggregationa  >>i  oella  arranged  in  two 

rowa  in  the  nteroe;  D-E,  oyata  thai  have  attained  ii"'  normal  aise  eud  b<  i  om ated 

w ith  .1  iliin  epidennie— greatly  enlai ged.      ' Original  > 

PLATE  \\1. 

A  changed  arrangement  of  oyata  within  thenternaof  the  female  Angnillnla  which 
oi'tfu  oconia    greatly  enlarged.    (Original.  I 


Bulletin  20,  Divmon  of  Entomology,  Dri  • 


PLATE    I. 


}   ]  ' ,  v 


i 


COW    PEA. 


Bulletin  2d.  DlviliOn  of  Entomology,  Oopt.  Ag 


PLATE    II. 


OKRA 


L 


Bulletin  20,  0i«iiion  gy,  Dopt   Agncultui*. 

PLATE    III. 


/ 


i 


RADISH 


^ 


Bulla' 


PLATE    IV. 


GRAPE 
Vitis  Vimfera  —  Black   Hamburg 


r 


i 


Builuif,  20,  D  ■  jmology,  Dtpt  A< 


MLATfc    V. 


PEACH 


Bultoli"  20,  0..  .   in  o(  Entomology,  D«pt   Agntuiiuro, 


PLATE    VI 


WEEPING    WILLOW 
Natural  size. 


1 


PLATt    VII 


FIG 
Natural  size. 


( 


"■r  *r 


PLATE    VIII. 


"ir 


OKRA       Sectpon   X  4 


PEACH      Secti. 


GRAPE       Section   X  4 


* 


WILLOW 
Natural  sue 


L 


Bulletin  20,  Olvflion  of   Entomology    D»pt    Agocul'uft, 

PLAT 


4a 


5a 


■^ 


10 


12 


13 


14 


15  16  17 

CYSTS  OF  ANGUILLULA. 


18 


B 

PLATE        X 


V 


I 


; 


• 


i  d 


26 


9 


■.■I 


V 


V 


10 


12 


Y 


f 

1 


^ 


15  16.  17  16 

CYSTS  OF  ANGUILLULA. 


■7 


/• 


DEVELOPMENT  OF  ANGUILLULA. 


'  II*. 
PLATE     XII. 


.   a 


, 


f        8 


' 


% 


DEVELOPMENT  OF  ANGUILLULA. 


Bulletin  20,  Oivition  of  Entomology,  D*pt.  Agriculture. 

PLATE    XIII 


W 


DEVELOPMENT  OF  ANGUILLULA. 


jltuce. 

PLATE    XIV. 


. 


S\ 


V 


B 


ft 


V 


'V' 


V\ 


I 


B. 


GROWTH  AND  CHANGES  IN  THE  FEMALE  ANGUILLULA 


PL  A' 


CHANGES  IN  THE  FEMALE  ANGUILLULA. 


PLATE     XVI 


15  I* 

-     ,n 


J500 


CHANGES  IN  FORM  OF  THE  FEMALE  ANGUILLULA. 


PLATE     XVII 


CHANGES  IN  FORM  OF  THE  FEMALE  ANGUILLULA. 


.'0,   O'K'lion  n(    EntomelOO  .lluro, 

PLATE      • 


GRAVID  FEMALE  ANGUILLULA,  SHOWING  CYSTS  IN  UTERO. 


Bulletin  20.  Ovmon  ol  Entomotof) 

PLATE     XIX. 


FEMALE  ANGUILLULA,  SHOWING  EXPULSION  OF  YOUNG. 


I,  Oh  ilturt. 

PLATE   XX 


B-C 


ARRANGEMENT  OF  CYSTS  IN  FEMALE  ANGUILLULA  IN  UTERO. 


Sullvtin  20,  I 

PLATE! 


: 


•   ••> 


■'■■ 


ARRANGEMENT  OF  CYSTS  IN  FEMALE  ANGUILLULA  IN  UTERO. 


Slip 


